For the Nodes and Protocols quest, you need to access 15 sleeper nodes, which means you need to grind out 60 Resonate Stems to craft the 15 necessary Override Frequencies. The 15 sleeper nodes required are NOT RETROACTIVE! So save your Resonate Stems until this quest is active.

You can earn Resonate Stems the following ways:

1 Resonate Stem per Public Event

2 Resonate Stems per Heroic Public Event

1 Resonate Stem per Lost Sector looted

1 Resonate Stem per “VIP” roaming boss enemy killed

1 Resonate Stem per Patrol completed

Resonate Stem Farming Techniques

Running the Lost Sector in the Glacial Drift over and over

When a Public Event is active, you can also pick up Patrol missions and complete them while a part of the Public Event. Shoot an enemy or two to join the Public Event, then run off and pick up a Patrol.
Only pick up Kill Patrols and Item Collection Patrols. These two types of Patrols will keep you close enough to the Public Event to complete both challenges at the same time.